Trial of the Safety and Efficacy of Epcoritamab in Japanese Subjects With Relapsed or Refractory (R/R) B-Cell Non-Hodgkin Lymphoma (R/R B-NHL)

Main Inclusion Criteria:

• Must be at least 20 years of age, inclusive

• Japanese participants

• CD20 positivity at representative tumor biopsy

1. Part 1:

1. Diffuse large B-cell lymphoma (de novo or histologically transformed)
2. High-grade B-cell lymphoma
3. Primary mediastinal large B-cell lymphoma
4. Follicular lymphoma
5. Marginal zone lymphoma (nodal, extranodal of mucosa-associated lymphoid tissue, or splenic)
6. Small lymphocytic lymphoma
7. Part 2 :

1. Arm 1:
2. Diffuse large B-cell lymphoma (de novo or histologically transformed)
3. Follicular lymphoma grade 1-3A
4. Relapsed or refractory disease and previously treated with at least 2 lines of systemic antineoplastic therapy including at least 1 anti-CD20 monoclonal antibody (mAb)-containing therapy.
5. Measurable disease by computed tomography (CT), magnetic resonance imaging (MRI) or positron emission tomography (PET)-CT scan

Arm 2:

1. • R/R FL grade 1, 2 or 3a, stage II, III, or IV, without evidence of transformation.
2. Previously treated with at least 1 prior anti-neoplastic agent, including anti-CD20 antibody
3. Must have a need for treatment initiation based on symptoms and/or disease burden (Groupe d'Etude des Lymphomes Folliculaires [GELF] criteria)
4. Eligible to receive R2 per investigator determination

1. Arm 3:
2. One of following confirmed histologies (de novo or histologically transformed from FL or nodal marginal zone lymphoma) :

1. o DLBCL, not otherwise specified (NOS)
2. "Double-hit" or "triple-hit" DLBCL
3. FL Grade 3B.
4. T-cell/histiocyte rich large B-cell lymphoma (LBCL)
5. International Prognostic Index (IPI) score ≥3
6. No prior therapy for DLBCL or FL grade 3B (G3B) other than nodal biopsy, corticosteroids, or palliative radiotherapy.
7. Eligible to receive R-CHOP per investigator determination

1. Arm 4:
2. One of following confirmed histologies (de novo or histologically transformed from FL or nodal marginal zone lymphoma) including:

o DLBCL, NOS.

1. o "Double-hit" or "triple-hit" DLBCL
2. FL Grade 3B.
3. T-cell/histiocyte rich LBCL
4. Relapsed or refractory to at least one prior therapy including at least one prior anti-CD20 antibody.
5. Either failed prior autologous hematopoietic stem cell transplantation (ASCT), or ineligible for autologous hematopoietic stem-cell transplantation (HSCT)
6. Eligible to receive GemOx per investigator determination

Arm 5:

• History of histologically confirmed CD20+ FL Grade 1-3a without evidence of transformation.

• In CR or PR per Lugano criteria following first-line or second-line treatment with SOC regimen, including anti-CD20 antibody, and last dose of SOC within 6 months prior to enrollment

Main Exclusion Criteria:

• Primary central nervous system (CNS) lymphoma or CNS involvement by lymphoma at screening

• Participants not eligible for high dose therapy with autologous hematopoietic stem cell transplantation due to personal choice, social issues, or similar

• Known clinically significant cardiac disease

• Chronic ongoing infectious diseases requiring treatment (excluding prophylactic treatment)

Exclusion criteria for Part 2, Arms 2 through 5:

Arm 2:

• FL Grade 3b

1. • Histologic evidence of transformation to an aggressive lymphoma
2. Contraindication to rituximab or lenalidomide
3. Unwilling or unable to take aspirin prophylaxis or prophylactic anticoagulant as clinically indicated

Arm 3:

• Contraindication to any of the individual drugs of the R-CHOP regimen

1. Arm 4:
2. Contraindication to any of the individual drugs of the GemOx regimen

1. Arm 5:
2. FL Grade 3b
3. Histologic evidence of transformation to an aggressive lymphoma